A Clinical Trials of Adsorbed Cell-free DPT Vaccine (Five-component)

This is a randomized, blinded, controlled phase II and III clinical trial evaluating the immunogenicity and safety of adsorbed cell-free DPT vaccine. 320 subjects aged 7 years and older in the phase II were divided into two age groups, the ≥18 years group and the 7-17 years group, and randomized 3:1 to receive the trial vaccine Tdcp versus the control vaccine PPV23. 1500 subjects in the phase III were divided into 3 age subgroups. 780 subjects were planned to be enrolled in the 6-year-old group and randomized 1:1 to receive the experimental vaccine Tdcp versus the control vaccine DTaP, and 360 subjects were planned to be enrolled in each of the 7-17 and ≥18 age groups and randomized 3:1 to receive the experimental vaccine Tdcp versus the control vaccine PPV23.